v0.9.0

Breaking changes:

• gradient and hessian are no longer exported; use Interpolations.gradient and Interpolations.hessian.
• interpolate objects now check bounds, and throw an error if you try to evaluate them at locations beyond the edge of their interpolation domain; use extrapolate if you need out-of-bounds evaluation
• For quadratic and cubic interpolation, interpolate! now returns an object whose axes are narrowed by the amount of padding needed on the array edges. This preserves correspondence between input indices and output indices. See https://julialang.org/blog/2017/04/offset-arrays for more information.
• The parametrization of some types has changed; this does not affect users of the "exported" interface, but does break packages that performed manual construction of explicit types.

Changes with deprecation warnings:

• itp[i...] should be replaced with itp(i...).
• OnGrid and OnCell should now be placed inside the boundary condition (e.g., Flat(OnGrid())), and should only be used for quadratic and cubic interpolation.
• the extrapolation boundary condition Linear was changed to Line, to be consistent with interpolation boundary conditions.

• In future versions itp[i...] may be interpreted with reference to the parent array's indices rather than the knots supplied by the user (relevant for scale and Gridded). If you fix the existing deprecation warnings then you should be prepared for this change.